If you’ve tuned in to the news in recent months, you’ve likely heard the word “antifa,” short for the anti-fascist movement. In the aftermath of the August Unite the Right rally in Charlottesville, Va., where white nationalists clashed with counterprotesters, historian Mark Bray has become known as an expert on antifa philosophy and strategy. A visiting scholar at Dartmouth College, the former Occupy Wall Street organizer has offered commentary on NBC and Vermont Public Radio’s “Vermont Edition.” At Phoenix Books Burlington, Bray leads a discussion of his new title Antifa: The Anti-Fascist Handbook, which outlines the long history of this movement.